To further improve sample material sampling accuracy by providing a first stylus at least whose tip is arranged within a chamber and a second stylus whose tip is opposed to the tip of the first stylus and which is capable of making relative movement for the first stylus.

By driving an actuator 24 on the side of an auxiliary stylus 12, the tip of the auxiliary stylus 12 is projected from the tip of a capillary tube 11. The surface of the tip of solution containing a sample material moves in the direction of a sampling stylus 8, being stuck to the tip of the auxiliary stylus 12. When the auxiliary stylus 12 is moved, lower potential is imparted to the sampling stylus 8 than the auxiliary stylus 12 and a tailor cone is generated at the tip of solution containing the sampling material which is positively charged. A very small droplet containing the sampling material is stuck to the tip of the sampling stylus 8 from the tip of the tailor cone. The solution at the tip of the auxiliary stylus 12 is stuck to the tip of the sampling stylus 8. Thus, the liquid shape at the tip of the capillary tube 11 can be controlled stably.